[PATCH 01/35] drm/amd/display: Use udelay when waiting between aux retries

[sylvain.bertrand at gmail.com]

On Fri, Feb 01, 2019 at 09:20:56PM +0000, Wentland, Harry wrote:
> DRM's AUX code uses usleep_range in drm_dp_dpcd_access.

My bad, forgot about the usleep_range switch. That said AUX_RETRY_INTERVAL is
500 us, with a usleep_range top bound of 600 us.

Then, it would mean DC DP timeout retries would happen after ~1ms, and drm
~600us. Additionaly, it seems that the number of retries are 3 in drm code and
7 in DC code. 

I may be wrong, but it seems DC code is much more "insisting" on auxchannel
(edid retrieval) and much more forgiving on monitor ability to timeout in
time (~1ms).

If I did read the code the right way, it may be more reasonable to have similar
behavior in drm code than in DC code, right?

-- 
Sylvain